Reciprocal folding dynamics in cellular networks at the stroma-basement membrane interface

Area of Science:

• Biophysics
• Developmental Biology
• Tissue Engineering

Background:

• The basement membrane (BM) separates epithelial and stromal layers, but the BM-stroma interface's role in morphogenesis is unclear.
• Most research focuses on the epithelium-BM complex, neglecting the underlying stromal contributions to tissue development.

Purpose of the Study:

• To investigate how forces from the stromal layer influence tissue morphogenesis at the BM-stroma interface.
• To elucidate the mechanism by which stromal cells interact with the basement membrane to drive tissue surface pattern formation.

Main Methods:

• Development of a collagen-based, nanometer-thick engineered basement membrane.
• Analysis of mechanical instability, polarized tractional forces, and topographic guidance of stromal cells.
• Observation of recursive interactions between stromal cells and basement membrane folding.

Main Results:

• Stromal cell traction forces induce folding at the BM-stroma interface.
• Stromal cell migration is guided by folding, leading to recursive folding and network formation.
• The stiffness difference between stroma and BM dictates folding direction (invagination/evagination).

Conclusions:

• Stromal cell-BM interactions provide a rational mechanism for pattern formation in multi-layered tissues.
• This model explains how basement membrane folding, driven by stromal forces, creates complex tissue surface structures like evaginated networks.